Let-back mechanism for looms



D 2, 1924. 1 ,'51s,11s

F. J. NORRIS v LET-BACK MECHANISM FOR LOOMS Filed July 24, 1922 2 Sheets-Sheet 1 Fig.1.

InvenTor. FredericK d. Norms Aliys Dec, 2, 1924. 1,518,118

F. J. NORRIS LET-BAK MECHANISM FOR LOOMS Filed July 24, 1922 2 Sheets-Sheet 2 lnv enTor. Frederick J. Norris Y b zmz MAQW ATTys.

Patented Dec. 2, 1924.

STATES Parent tr es.

FREDERICK J. NORRIS, 0F FALL RIVER, MASSACHUSETTS, ASSIG-NOR 'IO' DRAPER COR- PORATION, OF HOPEIDALE, MASSACHUSETTS, A CORPORATION OF MAINE.

LET-BACK MECHANISM FOR LOOMS.

Application filled. July 24, 1922. Serial No. 576,974.

To all whom it may concern:

Be it known that I, Fnnnnnror; J. NORRIS, a citizen of the United States, and resident of Fall River, county of Bristol, State of hlassachusetts, have invented an Improvement in Let-Back Mechanism for Looms, of which the following description, in connection with the acconmanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to improvements in let-back mechanisms for looms and the principal object thereof is to provide the take-up with means which are only manually operable to let back the take up mechanism.

In usual loom constructions, which are provided with knock-off mechanisms, means are provided which are operable by the action of the knock-off mechanism in the stoppage of the loom to let back the take-up mechanism for the purpose of preventing thin places in the web of cloth.

The knock-oft mechanism in common looms of the nonautomatic type is usually actuated by a filling fork which detects an absence or failure of filling and initiates the action of the knock-off mechanism. The movementof the knock-off mechanism to stop the loom thereupon releases and lets back the take-up or sand roll as in many instances the shuttle makes two or three idle flights before the loom is finally arrested. In many instances the filling fork and the warp stop mechanism of the loom causes a knock-off and stoppage of the loom when there is no absence or failure of filling and in such instances the action of the knockoff in producing a let-back of the take-up roll causes a thick place in the fabric by reason of the released. tension upon the warp when the operation of the loomis resumed. This is very detrimental in certain types of fabric, such as, window shade cloth in which an absolute evenness of weave is required and often results in the waste of a consider able amount of cloth, or the rejection of cuts of such cloth of which a minimum of two hundred yards or more only will be accepted by the trade.

The object of the present invention is to provide a let-back mechanism which is operable only by manual control so that a perfect uniformity in the weave of the cloth tation of the take-up roll to permit the avoidance' of thin places in the fabric.

Other objects and features of the invention will more fully appear from the following description and the accompanying drawings and will be pointed out in the claims- A preferred embodiment of the invention is illustrated herein as applied to a loom having a usual form of take-up and letback mechanism.

In the drawings:

Fig. 1 is a plan View of the end portion of the loom to which the inventionis applied;

Fig. 2 is a view of the end portion of the loom embodying the invention viewed from the front toward the rear of the loom;

Fig. 3 is a sectional view on line 33 Fig.

2, illustrating the invention as applied to the take-up and let-back mechanism of the loom; and,

Fig. 4 is an enlarged detail view of a preferred form of let-back pawl.

Inasmuch as the present invention relates only to the take-up and let-back mechanism of the loom, only a sufficient portion of the mechanism of the loom is illustrated herein as is necessary to show the application ofthe present invention to a usual type of loom.

The portion of the loom illustrated herein comprises an end frame 1, a breast beam 2, a shipper stand extension 3 of the breast beam, the take-up and cloth rolls, the mechanism for actuating the same and a preferred embodiment of thepresent invention for controlling the let-back mechanism. The takeup or sand roll 4 and the cloth roll 5, which. is located beneath it, are carried by shafts which are journalled in suitable bearings in a standard 6 which is provided at its lower end or supported upon a bracket 7 upon the loom side 1 and is connected at its upper end to the breast beam. The shaft of the take-up or sand roll at is provided with a gear 8 which is driven by a pinion 9 upon a stud shaft 10 mounted in the standard 6. The pinion 9 is formed integral with or connected to a ratchet wheel 11 which is rotated preferably by a gravity pawl 12 which is pivotally mounted upon a stud 13 upon the end of a lever lt which is oscillated vertically by a suitable cam upon the cam shaft of the machine (not shown) or from any other suitable source, the lever 1 1 being pivoted upon a stud 15 on the standard 6.

A detent pawl 16, which desirably is adjustably mounted upon a stud 17 on the standard 6, is provided with a toothed end portion 18 which engages the teeth of the ratchet wheel and is also provided with an adjustable arm or stop 19 which underlies the gravity pawl 12 and serves to limit the swinging movement of the pawl in such a manner that it will pass over a desired num ber of teeth upon each oscillation of the actuating lever 14.

The arm or stop 19 desirably is in the form of a rod which is slidably mounted in a boss 20 on the detent pawl 16 and is secured in adjusted position by a set screw 21. The end portion of the rod 19 as shown is bent downwardly and offset at right angles to lie beneath the ratchet actuating pawl 12 which is provided with a curved or camshaped lower end portion. The detent pawl is provided with an upwardly extending arm 22 which is adapted to be engaged by a releasing lever for the purpose of removing the detent pawl and with it the actuating pawl from engagementwith the ratchet wheel.

In previous constructions a lever, operated by the filling fork upon detection of absence or failure of filling, engaged and operated the arm 22 of the detent pawl and thereby released said detent pawl and actuating paw] from engagement with the ratchet wheel upon detection of failure or absence of filling.

In the present invention this lever mechanism is eliminated and the detent and ac tuating pawls placed solely under control of manually operable releasing means.

In the present construction, as in the early constructions, a filling fork 23 is pivotally mounted upon a slide 2 1 which is reciprocable in a stand 25 carried by the breast beam, the slide being adapted to engage and operate a knock-elf lever 26 upon detection of absence or failure of filling in the usual manner. The lzuoclcolf lever 26 is illustrated herein as pivotally mounted upon a stud 27 upon the shipper stand and operates when actuated to move the shipper 28 laterally out of engagement with the shoulder in the usual shipper stand slot 29. The shipper 28 as illustrated herein is provided with a resident lower portion. 30 which is secured to the loom side and serves, when the shipper is released by the knocl'c off, to swing the upper end of the shipper inwardly, toward the loom side, thereby moving the usual clutch-actuating lever which is provided with a bifurcated end portion 31 embracing the shipper lever in such a manner as to disengage the clutch members and effect a stoppage of the loom.

In previous constructions means operable by the filling fork slide were provided to release the ratchet actuating pawl and the detent pawl from engagement with the ratchet upon detection by the filling fork of failure or absence of filling. In the present construction this automatic releasing device is eliminated although the drawing illustrates a portion of the lever which formerly was employed for this purpose.

The portion of this automatic releasing device which is illustrated herein comprises an arm 32 having a downwardly curved end which normally is positioned between the shipper 26 and the end of the filling fork slide 2 1. This arm is pivotally mounted upon a shaft or bolt 33 which, for convenience in assembling, is adjustably mounted in a slot in a bracket 34 which is formed on the web 35 of the stand 6.

In previous constructions the arm was provided with an extension beyond the pivotal shaft 33 which was adapted to engage the upwardly extending arm of the detent pawl. In the present construction the downwardly depending arm has been removed so that the arm 32 illustrated herein is without function and is merely illustrated to show the adaptation of the present .invention to an old type of loom.

The manually operable releasing device for the actuating and detent pawls comprises a level 36 which is also pivotally mounted upon the shaft or bolt 33 and is provided at its upper end with a handle 37 adaptedto be grasped by the operator. l he lever 36 has an arm 38, extending down wardly below the pivotal shaft 33, provided with a lateral extension 39 which is adapted to engage the upwardly extending arm 22 of the detent pawl 16. The lever 36 also is provided with another downwardly and rearwardly extending arm 10 having at its end a counterweight 11 which tends normally to swing the handle 37 reamvardly and to position the arm 38 of the releasing lever 36 out of operative relation to the an of the detent pawl so that any '1' danger of interference with the tu leratiou of the latter is prevented.

It will thus be noted that the actuating and detent pawls remain in engagement with the ratchet which operates the tal c-up during the stoppage, as well as the running of the loom, so that no let-back of the tale up roll can occur without the manual operation of the releasing lever; consequently. it the loom is stopped for any other reason than failure or absence of filling the takeup is immediately actuated when the loom again started so that a thick place is prevented. hen the loom is automatically stopped by reason of absence or failure of filling the releasing lever is manually oper ated to let back the take-up roll sufliciently illustrated herein comprises an arm or link 42 having at its upper end a tooth 43 to en gage the teeth of the ratchet 11 and at its lower end a slot 44 which slidably engages a stud 45 projecting from a bracket 46 which desirably is adjustably connected to the loom B which it is wound.

side 1 by a bolt and slot connection 47. The stud is provided with a head 48 which desirably is elongated or oval in form so that it may be passed through the slot 44 when the pawl is in substantially vertical position, but will serve to retain the pawl from disengagement with the stud when the pawl is swung to its operative position illustrated in Fig. 3.

The slot 44 is of sufficient length to provide the necessary lost motion for the letback pawl to permit the required amount of retrograde rotation for the desired let-back of the take-up roll.

As it is desirable to provide means for adjusting the amount of let-back for various conditions of weaving means are provided for limiting the amount of lost motion of the link. In the preferred construction illustrated this is accomplished by providing a series of holes 49 in the walls of the slot 44 and introducing a pin 50 in the hole which is located at a distance from the end of the slot 44 which will give the required amount of let-back when the actuating and detent pawls are released from engagement with the ratchet 11.

In the operation of the loom the web of cloth 51 is carried over the breast beam and thence rearwardly over the take-up or sand roll. downwardly around the lower portion of the cloth roll and thence preferably upwardly around. the take-up or sand roll, and finally downwardlv to the cloth roll upon By reason of this arrangement a uniform take-up and tension is applied to the cloth.

The take-up roll is operated as above described by the vertical oscillation of the lever 14 which carries at its end the pivotally mounted gravity pawl 12 which engages the teeth of the ratchet 11. During the upward movement of the lever 14 the pawl 12 is forced downwardly thus rotating the ratchet 11 in a counter-clock-wise direction and, acting through the pinion 9 and gear 8, rotates the take-up roll in a clock-wise direction and through the web of cloth rotates the cloth roll in a direction to wind the cloth thereupon. As the ratchet 11 is thus rotated the tooth 18 of the detent pawl 16 rides over the teeth of the ratchet and by engagement with the successive teeth prevents retrograde rotation of the ratchet when the actuating pawl 12 is retracted. Upon downward movement of the lever 14 the gravity pawl is raised and rides over the teeth of the ratchet wheel until it is arrested by the adjustable stop 19 which is carried by the gravity pawl. By adjusting the stop 19 the amplitude of movement of the gravity pawl 12 may be limited so that it will pass over the desired number of teeth to effect the proper take-up action.

In case the 100111 is stopped for any reason whatever there will be no automatic re- 1 i lease of the actuating or take-up pawls from engagement with the ratchet'and, consequently, no let-back; so that if the stoppage of the loom is produced by a false action of the filling fork, or for any other reason, there will be no let-back and, consequently, no danger of the production of a thick place in the goods upon resumption of the weaving operation. If the stoppage of the loom is produced byfailure or absence of filling the manually operable releasing lever may be actuated to release the actuating and detent pawls so as to permit the necessary let-back to avoid a thin place upon resumption of the weaving operation. By placing the pin 50 in the proper one of the holes 49 in the letback pawl the required amount of let-back may be provided for the particular conditions under which the loom is operated.

It has been found in practice that the elimination of the usual automatic control of the let-back mechanism and the employment only of the manual control therefor has resulted in the production of uniform weave in cuts of cloth, such as, window shades which require exceedingly careful weaving and in which the presence of even a narrow thick place or thin place is very detrimental to the goods.

It will be understood that the embodiment of the invention disclosed herein is of an illustrative character and is not restrictive and that the principle of the invention may be applied to other types of looms than that herein illustrated and that various changes iii in form, construction and arrangement of parts necessary to embody the invention in any suitable type of loom may be made within the spirit and scope of the following claims.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is:

1. In a loom comprising knock-off mechanism, a take-up roll and means for rotating said take-up roll including a ratchet, a reciprocable actuating lever having a gravity pawl engaging said ratchet, a detent pawl underlying said gravity pawl normally acting to prevent let-back both during the operation and stoppage of the loom, but operable when raised to raise said gravity pawl out of engagement with said ratchet, and upwardly extending arm on said detent pawl, a. manually operable pawl-releasing lever having an arm positioned to engage the upwardly extending arm of said detent pawl upon manual actuation of said pawlreleas- 111g lever, means acting normally to hold said pawl-actuating lever from such engagement and a let-back pawl engaging said ratchet having means for limiting the retrograde rotation of said take-up roll upon the release of said actuating and detent pawls.

2. In a loom comprising knock-oil mechanism, a take-up roll and means for rotating said takeup roll including a ratchet, a re ciprocable actuating lever having a gravity pawl pivotally mounted thereon engaging said ratchet, a detent pawl having an'adjustable stop underlying said gravity pawl and acting to limit its tooth-engaging movement and also operable to raise said gravity pawl upon release of said detent pawl, an arm extending upwardly from said detent pawl, a manually operable pawl-releasing lever having an arm positioned to be swung into actuating engagement with the upwardly extending arm of said detent pawl, a counterweight upon said releasing lever acting normally to hold said lever out of engagement with the arm on the detent pawl and pivotally and reciproeably mounted letback pawl engaging said ratchet acting to limit the retrograde rotation of said take-up roll when said actuating and detent pawls are released;

In testimony whereof, I have signed my name to this specification.

FREDERICK J. NORRIS 

